Add getopts-test demo crate

Cargo.toml

@@ -21,3 +21,8 @@ log = "0.4"
 default = ["unicode"]
 rustc-dep-of-std = ["std", "core"]
 unicode = ["dep:unicode-width"]
+
+[workspace]
+members = ["getopts-test"]
+default-members = [".", "getopts-test"]
+resolver = "2"

getopts-test/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "getopts-test"
+version = "0.0.0"
+edition = "2021"
+rust-version = "1.66"
+publish = false
+
+[dependencies]
+# Preserve the workspace's `--no-default-features` test coverage.
+getopts = { path = "..", default-features = false }
+
+[dev-dependencies]
+assert_cmd = "2"
+predicates = "3"

getopts-test/src/main.rs

@@ -0,0 +1,58 @@
+use getopts::{Matches, Options};
+use std::{env, process};
+
+const BRIEF: &str = "Usage: getopts-test [options] INPUT...";
+
+fn options() -> Options {
+    let mut options = Options::new();
+    options.optflagmulti("v", "verbose", "increase verbosity");
+    options.optopt("o", "output", "write output to FILE", "FILE");
+    options.optmulti("I", "include", "add DIR to the include path", "DIR");
+    options.optflagopt("", "color", "control color output", "WHEN");
+    options.optflag("h", "help", "print this help menu");
+    options
+}
+
+fn fail(options: &Options, message: impl std::fmt::Display) -> ! {
+    eprintln!("error: {message}");
+    eprintln!();
+    eprint!("{}", options.usage(BRIEF));
+    process::exit(2);
+}
+
+fn print_matches(matches: &Matches) {
+    let output = matches
+        .opt_str("output")
+        .unwrap_or_else(|| "<stdout>".into());
+    let color = matches
+        .opt_default("color", "auto")
+        .unwrap_or_else(|| "never".into());
+
+    println!("verbosity: {}", matches.opt_count("verbose"));
+    println!("output: {output}");
+    println!("color: {color}");
+
+    for include in matches.opt_strs("include") {
+        println!("include: {include}");
+    }
+    for input in &matches.free {
+        println!("input: {input}");
+    }
+}
+
+fn main() {
+    let options = options();
+    let matches = options
+        .parse(env::args().skip(1))
+        .unwrap_or_else(|error| fail(&options, error));
+
+    if matches.opt_present("help") {
+        print!("{}", options.usage(BRIEF));
+        return;
+    }
+    if matches.free.is_empty() {
+        fail(&options, "at least one INPUT is required");
+    }
+
+    print_matches(&matches);
+}

getopts-test/tests/cli.rs

@@ -0,0 +1,77 @@
+use assert_cmd::Command;
+use predicates::prelude::*;
+
+const BRIEF: &str = "Usage: getopts-test [options] INPUT...";
+
+fn command() -> Command {
+    Command::new(env!("CARGO_BIN_EXE_getopts-test"))
+}
+
+#[test]
+fn parses_options_and_positional_arguments() {
+    command()
+        .args([
+            "-vv",
+            "--output",
+            "report.txt",
+            "-I",
+            "src",
+            "--include",
+            "tests",
+            "--color=always",
+            "input.txt",
+            "extra.txt",
+        ])
+        .assert()
+        .success()
+        .stdout(
+            "verbosity: 2\n\
+             output: report.txt\n\
+             color: always\n\
+             include: src\n\
+             include: tests\n\
+             input: input.txt\n\
+             input: extra.txt\n",
+        )
+        .stderr("");
+}
+
+#[test]
+fn uses_defaults_and_honors_the_option_terminator() {
+    command()
+        .args(["--color", "--", "-input.txt"])
+        .assert()
+        .success()
+        .stdout(
+            "verbosity: 0\n\
+             output: <stdout>\n\
+             color: auto\n\
+             input: -input.txt\n",
+        )
+        .stderr("");
+}
+
+#[test]
+fn prints_help() {
+    command()
+        .arg("--help")
+        .assert()
+        .success()
+        .stdout(predicate::str::contains(BRIEF))
+        .stdout(predicate::str::contains("--color [WHEN]"))
+        .stderr("");
+}
+
+#[test]
+fn reports_parse_and_validation_errors() {
+    command()
+        .arg("--unknown")
+        .assert()
+        .code(2)
+        .stderr(predicate::str::contains("Unrecognized option"));
+
+    command()
+        .assert()
+        .code(2)
+        .stderr(predicate::str::contains("at least one INPUT is required"));
+}